Radiation Oncology
Expert insights on radiation treatment planning, techniques, toxicity management, and multimodal cancer care.
Recent Discussions
Is there a PSA value below which you would not offer salvage radiation post-prostatectomy?
I am commonly asked the inverse question: if I use a "PSA cutoff" whereby a rise beyond this value will strongly favor treatment with post-op radiation. I think it is difficult to have a set value that applies for all patients, as the decision to treat should be individualized to patient and disease...
How would you adjust your CTV for a locally advanced rectal cancer case with invasion of the prostate?
I’m not aware of any “high level” guidance on this specific question. Most cases I see have limited invasion of the peripheral zone of the prostate and/or seminal vesicles. With the assistance of a registered MRI, I contour the gross primary tumor and add at least a 1 cm margin into the prostate. I ...
How would you treat a carcinoma in situ of the larynx with involvement of the false cord and arytenoid mucosal surface?
63 Gy/28 fractions larynx only
What dose would you use for a plaque brachytherapy for a melanoma involving the iris?
The following isotopes have been used for radioactive plaque therapy to treat choroidal melanomas: 125I, 103Pd, and 131Cs as low-energy seeds, and 106Ru as β emitter. The dose used for uveal melanomas is between 80-90Gy with most studies reporting doses ~85 Shields et al., PMID 10980767. In this lar...
For esophageal and gastroesophageal junction cancers, which lymph nodes are metastatic versus regional?
I would say the short answer is no, hilar nodes are not regional nodes for esophageal of gastroesophageal junction cancers. The long answer would require a definition of what we're talking about when we say lymph nodes are "regional". This may have different definitions depending on the setting. F...
What BED10 do you aim for when prescribing hypofractionated treatment for ultra-central tumors of the lung?
It depends on how you define "ultra-central." If the tumor is within 1 cm but not touching a more distal bronchus like lobar bronchus, I may still use a prescription dose of 50 Gy in 5 fractions, while limiting hotspots to 120% and allowing some undercoverage of PTV to meet proximal TBT constraints....
Is there any evidence that radiotherapy can worsen balance, dizziness, or vertigo in patients treated for vestibular schwannoma due to transient edema?
While the answer from Dr. @Dr. First Last addresses a much broader category of patients treated with SRS, we have looked specifically at post radiation side effects after treatment of vestibular schwannomas treated with either SRS (12.5 Gy), hypofractionated SRS (hSRT with 5 fractions of 5 Gy), or c...
What is your cochlear dose constraint when treating acoustic neuromas with SRS in a patient with intact hearing?
The critical components of hearing susceptible to radiation toxicity of vestibular schwannoma treatment include acoustic nerve, cochlea, and brain stem. It is unclear which structure is responsible. It helps to understand the continuum of fibers from the endolymphatic receptors from cochlea to form ...
What are the common side effects that you observe with TTFields?
I think most patients do tolerate TTF. I’ve seen patients with concerns of skin irritation, but I think the bigger issue is the inconvenience and aesthetics.
What is the risk of secondary malignancy and/or conversion to MPNST for patients with NF-1 who undergo radiation?
Broadly speaking, this is certainly a possibility and this has been a reason why the community has triaged the application of radiotherapy to more high-risk cases (Williams et al., PMID 19117870). Just playing out the numbers independent of the application of radiotherapy, 100% of NF1 patients will ...